Method And Device For Producing A Cast Workpiece

ABSTRACT

A method and apparatus for producing a cast component with a wall in which at least one hollow chamber is formed. A hollow body for forming the hollow chamber is introduced into a casting tool by means of an apparatus, and liquid material is then supplied to the casting tool so as to surround the hollow body and thereby form the hollow chamber in the cast wall. For the assembly movement of the hollow body into the casting tool, the hollow body is received by a transporting device in which the hollow body is positively guided by its connection body areas.

PRIORITY CLAIM

This is a U.S. national stage of application No. PCT/EP2014/052797, filed on Feb. 13, 2014. Priority is claimed on the following application: Country: Europe, Application No.: 13159480.6, Filed: Mar. 15, 2013, the content of which is/are incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention is directed to methods and apparatus for producing a cast workpiece.

BACKGROUND OF THE INVENTION

Generally, cast workpieces in a wall can also have flow channels or hollow areas. In the case of a die cast component having a hollow area or flow channel, for example, two production methods can be pursued. Where a flow channel is exactly straight, a tool can have a corresponding core for forming the flow channel. This procedure however allows for only simple, straight channel shapes. The length of the channel is also limited because the core must be removed from the workpiece.

In a common manufacturing process, a hollow body by means of which the flow channel to be produced is formed in the die cast component is produced as a preassembly component and is inserted into the die casting tool. The material injected into the die casting mold surrounds the hollow body which remains in the wall of the die cast component. Consequently, the pre-produced hollow body must have a quality, particularly dimensional stability, suited to the final product.

A pre-produced hollow body, particularly one with a complicated three-dimensional shape, is subject to a certain manufacturing tolerance which is also reflected, for example, in the bending radii. While faulty parts are when possible sorted out before they are fed into the production flow, not every dimensional deviation is readily detectable for early removal from further processing. In the ensuing production flow, the hollow bodies are delivered without first being sorted and are fed to a magazine. Slight deviations are compensated during the feeding into the magazine so that the hollow body then fits in the magazine.

Subsequently in the production flow, a charging robot removes or grasps the hollow body by means of gripping tongs and guides the hollow body to the die casting tool. If the hollow body cannot be inserted exactly into the tool, for example because of shape deviations (e.g., if one hollow end does not occupy the predetermined assembly position), then in the simplest case an error report is sent by a sensor arrangement present at the die casting tool or die casting apparatus. Consequently, the delay or downtime between the process of producing two die cast components will be prolonged such that, for example, the die casting mold cools down in an unwanted manner. Where there are slighter deviations in shape, the die cast workpiece is produced but the channel dimensions may perhaps be unsuitable. This can result in a faulty part unfit for us and that can only be melted down.

By way of example, a source of error can arise where the gripping tongs can grasp the hollow body but, through an unfortunate combination of shape errors, the hollow body is inserted askew into the die casting tool. One obvious possible solution would be to provide the hollow body with tool surfaces with which the hollow body could be definitively grasped by the gripping tongs. Tool surfaces of this type would however render the hollow body more expensive and would also have negative results for the flow cross sections of a flow channel to be produced.

OBJECTS AND SUMMARY OF THE INVENTION

It is accordingly the object of the present invention to overcome the manufacturing problems, as for example described above, that are known from and present in the prior art.

In accordance with the invention, this object is met in that, for movement of the assembly into the casting tool, the hollow body is received by a transporting device in which the hollow body is positively guided by its connection body areas.

The position of the hollow body is previously defined outside of the casting tool. If a problem has already occurred during this process step because the tubular body cannot be received by the transporting device due to a flawed geometry, another such hollow body can be fed to the die casting tool simultaneously with or following a slight delay by using a second transporting device. This assumes that two defective parts will rarely serially follow, closely in time, one after the other. Consequently, in this manner the process of feeding a hollow body into the die casting tool can be uninterruptedly maintained such that no unnecessary cooling-off phases or conditions at the die casting tool need be tolerated.

In order to maintain an uninterrupted, defined assembly movement of the hollow body, the hollow body is moved out of the transporting device by the connection body areas of the hollow body into a takeover tool that forms part of the casting tool. The takeover tool takes over, from the transporting device, the guide position for that process phase when the hollow body has reached its predetermined assembly position in the casting tool.

According to an advantageous feature implemented in accord with an embodiment of the invention, the hollow body is pulled into the transporting device. If the hollow body has dimensional deviations, the hollow body can nevertheless be received by the transporting device through this pulling movement. The positive-guide function of the transporting device provides for compensation of slight deviations of the hollow body which, within limits, is elastic.

In a further advantageous and alternate embodiment of the inventive method, the hollow body is moved out of the transporting device by means of a pushing tool. The pushing tool can have a simple design and can exert high assembly forces with low wear. In a preferred form of this alternate embodiment, the pushing tool is constructed as a displaceable stop.

The transporting device advantageously has guide surfaces at which the hollow body abuts. Accordingly, the apparatus moving the hollow body into the transporting device need not assume a guide function. Consequently, the gripping function and, therefore, the grippers for the insertion movement into the transporting device are also simplified.

In a further embodiment of the invention, the guide surfaces have relief cuts which face one another and through which at least one angled portion of the hollow body can exit from the guide surfaces. The advantage of this construction and operation is that a U-shaped hollow body can also be moved into the transporting device through a simple pulling movement.

For transporting and transferring each hollow body in the casting tool without interruption, the transporting device includes at least one positive engagement surface which cooperates with a complementary positive engagement surface of the takeover tool.

In addition, the takeover tool has a receiving profile for the connection surfaces of the hollow body. As a consequence, the hollow body is always transferred from the transporting device to the casting tool in a defined manner. The two ends of the hollow body are preferably provided in the form of connection surfaces.

The apparatus may include a sensor arrangement for detecting at least one movement parameter of the pushing tool. This enables detection of whether a component part is present in the transporting device and, additionally, whether the assembly position has been reached in the casting tool, as for example by measuring or sensing an increase in force at the pushing tool.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1A diagrammatically depicts in cross section a transporting device in accordance with the invention for feeding a hollow body into a casting tool, shown in a first position of the transporting device;

FIG. 1B diagrammatically depicts in cross section the transporting device of FIG. 1A shown in a second position of the transporting device in conjunction with the casting tool;

FIG. 2 is a bottom plan view of the transporting device as depicted in FIG. 1 B; and

FIG. 3 is a cross-sectional detail of the transporting device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The process of producing a flow channel in a wall of a cast component part in accordance with the invention utilizes a hollow body 1 having an inner wall forming the flow channel. Thus, a hollow body 1 for use in the process is produced, the form of which exactly envelopes the predetermined flow channel. The hollow body 1 is preferably made of a metallic material. To simplify the production process, the hollow body 1 is fed to a magazine 3 in which the hollow body 1 occupies a defined initial assembly position. The hollow body 1, which may for example be U-shaped (as depicted herein), is positioned so as to be upright in the magazine 3. The hollow body is received by a transporting device 7 (FIG. 1A) for assembly movement of the hollow body 1 into a casting tool 5 (FIG. 1B).

FIGS. 2 and 3 depict several views of the transporting device 7. For the specific use with a U-shaped hollow body 1, the transporting device is provided with guide surfaces 9, 11 that form two respective open guide grooves 13, 15. During the assembly movement of body 1 into the casting tool 5, the hollow body 1 contacts the guide surfaces 9, 11 as shown in FIG. 2. The guide surfaces 9, 11 have relief cuts 17, 19 which face one another and through which at least one angled portion 21 of the hollow body 1 can exit from the respective guide surfaces 9, 11 and guide grooves 13, 15. The angled area 21 is formed by a connecting crosspiece of the hollow body 1 which connects its two parallel flow portions 23, 25. Of course, the hollow body 1 can instead have a completely different body contour. The guide surfaces 9, 11 form a hollow that defines an envelope suited to the specifications of the particular hollow body to be grasped and transported by the transporting device. Moreover, the dimensioning and angular positioning of the guide surfaces 9, 11 are configured to take into account the intended or desired manufacturing tolerances of the hollow body 1.

The transporting device 7 has at the ends thereof at least one positive engagement surface 27 for entry into a positive engagement connection or cooperation with a complementary positive engagement surface 29 of a takeover tool 31 as part of the casting tool 5. In the depicted and now-described illustrative embodiment of the transporting device 7, the positive engagement surface is formed as a journal sleeve that is engageable in a receiving sleeve which acts as takeover tool 31. In this embodiment and operation, the receiving sleeve centers the journal sleeve of the transporting device 7. Because of the way in which two journal sleeves are formed at the transporting device 7 in this particular illustrative embodiment, the hollow body 1 is guided in a certain and defined manner with respect to all spatial coordinates of the casting tool 5.

The takeover tool 31 defines a receiving profile 33 for connection body areas 35 of the hollow body 1. In the depicted embodiment, the receiving profile 33 may for example be constructed as a simple bore hole, assuming that the wall of the hollow body forms a simple annular cross section at both its ends. Of course, implementations in which the receiving profile 33 has a journal shape on which the hollow body is fitted can alternatively be provided for other forms of the body 1 and are within the intended scope and contemplation of the invention.

The inventive process is initiated as the hollow body 1 is received by the transporting device 7. The transporting device 7 is preferably moved so that it overlaps with the hollow body 1 and the body 1 is then pulled [upwardly, in the drawings,] out of the magazine 3. The hollow body 1 is initially positioned in the magazine 3 in the same basic orientation in which the cast part is to be fabricated, and the body 1 is received into and grasped by the transporting device 7 by means of a gripper 37 which lowers the transporting device 7 into engagement with the hollow body 1. In this manner, the guide surfaces 9, 11 ensure precise receipt and positioning of the hollow body 1 within the transporting device 7. If the hollow body 1 has slight angular errors, the hollow body 1 can nevertheless be pulled into the transporting device 7 by its connection portion 21, and the guide surfaces 9, 11 will align the hollow body 1 within the framework by the further pull-in movement taking advantage of the inherent elasticity of the body 1.

The transporting device 7 can by way of example be carried by a robot which moves the transporting device 7 to the open casting tool 5. Of course, a manual transporting movement is also possible with correspondingly suitable component part sizes. When the hollow body 1 has reached the predetermined assembly position in the transporting device 7, the positive engagement surface 27 of the transporting device 7 and the at least one complementary positive engagement surface 29 of the takeover tool 31 provide for a positive engagement of the transporting device 7 in the takeover tool 31 and casting tool 5. With this positive engagement, the hollow body 1 is moved out of (i.e. released from) the transporting device 7 by means of a displaceable stop 39 that acts as pushing tool. In this manner, the connection body areas 35 of the hollow body 1 positively engage in the receiving profile 33 of the takeover tool 31.

The displacing movement of the stop 39 can be monitored in a variety of ways by means of a sensor arrangement 41. For example, a predetermined end position of the motion of the stop 39 can be detected by an optical sensor. If the sensor arrangement indicates that this predetermined end position has not been reached, then it must be assumed that the hollow body 1 was not correctly transferred to the casting tool 5. The predetermined end position of the stop 39 can also be detected by means of a force measurement of the stop movement.

Through use of the transporting device 7 in accordance with the present invention, the feeding of the hollow body 1 from a parts reservoir, such as a magazine, to the casting tool 5 always proceeds in a controlled manner such that a faulty positioning of the hollow body 1 in the casting tool 5 is to a great extent eliminated. With the hollow body 1 properly fixed in the casting tool 5, the casting tool can then be closed and liquid material supplied to cast the desired part.

Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto. 

1-10. (canceled)
 11. A method for producing a cast component having a wall in which a predeterminately-contoured hollow chamber is defined using a hollow body having a contour complementary to the hollow chamber to be cast, comprising the steps of: introducing the hollow body into a casting tool by: receiving the hollow body by a transporting device, and moving the hollow body from the transporting device to the casting tool; and supplying liquid material to the casting tool so as to surround the moved hollow body and thereby define the predeterminately-contoured hollow chamber in the wall of the cast component; wherein the hollow body has connection body areas for positively guiding the hollow body as it is moved from the transporting device to the casting tool.
 12. The method of claim 11, wherein in said moving step the hollow body is moved using the connection body areas from the transporting device into a takeover tool that forms a part of the casting tool.
 13. The method of claim 11, wherein in said receiving step the hollow body is pulled into the transporting device.
 14. The method of claim 11, wherein in said moving step the hollow body is moved out of the transporting device by operation of a pushing tool.
 15. Apparatus for use in producing, in a casting tool, a cast component having a wall in which a predeterminately-contoured hollow chamber is defined using a hollow body having a contour complementary to the hollow chamber to be cast, comprising: a transporting device for receiving the hollow body from an initial location to transport the hollow body to the casting tool, said transporting device being configured with guide surfaces for abutment with the hollow body for engagement of the hollow body by the receiving transporting device.
 16. The apparatus of claim 15, wherein the hollow body has at least one angled portion and wherein the guide surfaces have relief cuts that face one another and through which at least one angled portion of the hollow body can exit its engagement with the guide surfaces of the transporting device.
 17. The apparatus of claim 15, further comprising a takeover tool that forms a part of the casting tool for receiving the hollow body from the transporting device as the hollow body is transported to the casting tool, wherein the takeover tool includes a first positive engagement surface and the transporting device has at least one second positive engagement surface configured to compliment the first positive engagement surface of the takeover tool for cooperative engagement of the first and second positive engagement surfaces as the hollow body is transported from the transporting device to the casting tool.
 18. The apparatus of claim 15, further comprising a takeover tool that forms a part of the casting tool for receiving the hollow body from the transporting device as the hollow body is transported to the casting tool, wherein the hollow body has connection body areas for positively guiding the hollow body as it is moved from the transporting device to the casting tool, and wherein the takeover tool has a receiving profile for receiving the connection body areas of the hollow body.
 19. The apparatus of claim 15, further comprising a pushing tool for moving the hollow body from the transporting device to the casting tool, said pushing tool comprising a displaceable stop. 